The video distribution industry (broadcast TV and Pay TV including satellite TV, cable TV and Telco TV) is actively transitioning from legacy broadcast distribution to Internet (IP-based) streaming delivery of its video assets.
Certain TV network broadcasters, such as CBS and ABC are offering some of their linear channels over IP as a continuous and unique feed using a Linear Origin. Such streaming content can be accessed for playback in real time or near-real time via a PC browser or via TV-specific services such as Apple TV or Roku.
Certain Pay TV service providers such as Comcast or Cablevision are offering subscribers the ability to store and playback on-demand and live content in the network. On-demand content is stored in general-purpose or dedicated servers, while live content is stored in network-based devices (N-DVR), cloud-based devices (C-DVR) or Live On-demand Origins (LOD). All these can be referred to as “Content Origination Systems” (COS). Such Content Origination Systems are hosted in a public or private cloud and provide the subscriber with capabilities similar to an in-home DVR by recording live events for live, near-live or deferred playback.
Content Origination Systems allow for on-demand access to linear (live TV) content. These systems enable the subscriber to catch up with live events (news, sports, weather), at any time, from the beginning of an event, while the event is still airing, or at any time after the event has ended.
Live and on-demand content delivery systems over IP utilize industry standards (such as HLS and DASH—e.g. ISO/IEC 23009-1) to define a media description (i.e. manifests (DASH) or playlist (HLS) depending on the delivery standards). The media description references audio and video media elements (i.e. segments or fragments depending on the delivery standards) and their associated metadata. Event media descriptions may reference one or multiple simultaneous audio and/or video tracks (“representations”), that may represent multiple audio languages, video resolutions, or camera angles.
The most efficient approach to deliver live video on-demand is to record a single copy of each event (“Common Copy”) and deliver it to all subscribers. However, due to applicable copyright and broadcasting regulations, certain legal restrictions can mandate that a unique copy of each event (“Private Copy”) is assigned to each subscriber. These requirements may be limited to certain content distributors, they may be limited to subscribers located in certain geographic regions and in certain jurisdictions and they may be limited to content copies originated from certain live channels.
The implementation of a COS with “Private Copy” capabilities can be very expensive and cumbersome to implement, because it requires to quickly and efficiently generate, maintain, retrieve and deliver a potentially large number of unique copies of otherwise identical content.
In general, the ability to generate, deliver, monitor and delete content copies must be available regardless of original event airtime and regardless of playback window. As an example, a subscriber may wish to watch an episode of an event that aired live the previous evening (catch-up), while another subscriber may wish to watch an event that started a few minutes ago and is still currently airing (start-over). In both scenarios sufficient individual copies of the event must be generated, delivered, and eventually disposed of with adequate reliability and performance to assure instant and continuous content access, smooth content playback and efficient system operation regardless of the number of channels being recorded, the number and duration of events being published, and the volume of subscribers accessing the content.
The timely availability, delivery and deletion of content copies is essential to the performance, efficiency and regulatory compliance of a COS operating in Private Copy mode. As an example, if an individual copy of an event is not yet available at the time that an individual subscriber requests it, the transaction will fail, and the resulting overall quality of service will be degraded. If at any time the content is delivered from a common copy instead of a unique Private Copy, the transaction will succeed but it will breach the unicity requirement, and the resulting compliance will be degraded. If there are no subscriber requests but the system still maintains multiple copies of an event, the system storage will be higher than required resulting in a cost overrun.